The present invention relates to anchoring plugs. More particularly, it relates to an anchoring plug which has an expander cone mounted on one end of a plug shaft for supporting an object, and an expansible sleeve which is expanded by the expander cone.
Anchoring plugs of the above mentioned general type are known in the art. One of such anchoring plugs is disclosed U.S. Pat. No. 4,640,654. In the anchoring plug disclosed in this document the pulling of the expander cone into the expansible sleeve is performed so that a screw which is arranged at the opposite end of the plug shaft abuts against an object to be mounted. During rotation of the screw the shaft and thereby the expander cone are pulled outwardly of the hole in which the anchoring plug is inserted. The expansible sleeve remains fixed stationarily in the hole and is expanded by the expander cone so that the expansible sleeve is pressed against the wall of the hole.
Such anchoring plugs are used for example in concrete masonry. When subsequent expansions of the holes occur, for example because of formation of cracks, there is the requirement that the anchoring plug is expanded to continue the reliable performance of its holding function. The post-expanding condition is however unfavorably affected in the anchoring plug which is anchored in a hole during pressing-on between the expander cone and the expansible sleeve. Under the action of high expanding forces the expansible sleeve can jam on the expander cone.